Extracorporeal Membrane Oxygenation (VA-ECMO) in Management of Cardiogenic Shock

Cardiogenic shock is a critical condition of low cardiac output resulting in insufficient systemic perfusion and end-organ dysfunction. Though significant advances have been achieved in reperfusion therapy and mechanical circulatory support, cardiogenic shock continues to be a life-threatening condition associated with a high rate of complications and excessively high patient mortality, reported to be between 35% and 50%. Extracorporeal membrane oxygenation can provide full cardiopulmonary support, has been increasingly used in the last two decades, and can be used to restore systemic end-organ hypoperfusion. However, a paucity of randomized controlled trials in combination with high complication and mortality rates suggest the need for more research to better define its efficacy, safety, and optimal patient selection. In this review, we provide an updated review on VA-ECMO, with an emphasis on its application in cardiogenic shock, including indications and contraindications, expected hemodynamic and echocardiographic findings, recommendations for weaning, complications, and outcomes. Furthermore, specific emphasis will be devoted to the two published randomized controlled trials recently presented in this setting.

Mechanical circulatory support in acute myocardial infarction and cardiogenic shock: Challenges and importance of randomized control trials

BACKGROUND

Acute myocardial infarction (AMI) complicated by cardiogenic shock (CS) is associated with significant morbidity and mortality.

METHODS

We provide an overview of previously conducted studies on the use of mechanical circulatory support (MCS) devices in the treatment of AMI-CS and difficulties which may be encountered in conducting such trials in the United States.

RESULTS

Well powered randomized control trials are difficult to conduct in a critically ill patient population due to physician preferences, perceived lack of equipoise and challenges obtaining informed consent.

CONCLUSIONS

With growth in utilization of MCS devices in patients with AMI-CS, efforts to perform well-powered, randomized control trials must be undertaken.

Acute kidney injury following left ventricular assist device implantation: Contemporary insights and future perspectives

Currently, an increasing number of patients with end-stage heart failure are being treated with left ventricular assist device (LVAD) therapy as bridge-to-transplantation, bridge-to-candidacy, or destination therapy (DT). Potential life-threatening complications may occur, specifically in the early post-operative phase, which positions LVAD implantation as a high-risk surgical procedure. Acute kidney injury (AKI) is a frequently observed complication after LVAD implantation and is associated with high morbidity and mortality. The rapidly growing number of LVAD implantations necessitates better approaches of identifying high-risk patients, optimizing peri-operative management, and preventing severe complications such as AKI. This holds especially true for those patients receiving an LVAD as DT, who are typically older (with higher burden of comorbidities) with impaired renal function and at increased post-operative risk. Herein we outline the definition, diagnosis, frequency, pathophysiology, and risk factors for AKI in patients with an LVAD. We also review possible strategies to prevent and manage AKI in this patient population.

Clinical application of intra-aortic balloon pump in patients with cardiogenic shock during the perioperative period of cardiac surgery

Intra-aortic balloon pumps (IABP) have saved many patients with cardiogenic shock during the perioperative period of cardiac surgery. However, the ideal insertion timing is controversial. In the present study, we aimed to optimize the insertion timing, in order to increase the survival rate of the patients. A total of 197 patients with cardiogenic shock during the perioperative period of cardiac surgery and implemented IABP from January 2011 to October 2015 were selected for the study. Patients were divided into five groups on the basis of application timing of IABP: 0–60, 61–120, 121–180, 181–240 and >240 min. The 30-day mortality, application rate of continuous renal replacement therapy (CRRT), duration of mechanical ventilation, duration of hospital stay and hospitalization charges were analyzed in the above groups. The risk factors related to mortality and the occurrence of IABP complications were also analyzed. The mortality in the 0–60, 61–120, 121–180, 181–240 and >240 min groups were 42.17, 36.6, 77.3, 72.7 and 79.3%, respectively. Earlier IABP insertion resulted in less patients receiving CRRT from acute renal failure and less daily hospitalization charges. However, the IABP application timing had no effect on indexes such as hospitalization duration, duration of mechanical ventilation and total hospitalization charges. Multifactor logistic regression analysis indicated that the independent risk factors of death in patients with cardiogenic shock during cardiac surgery were related to IABP support timing and vasoactive-inotropic score (VIS) before balloon insertion. In the first 120 min of cardiogenic shock during the perioperative period of cardiac surgery, IABP application decreased 30-day mortality. Mortality was related with VIS score of patients, which can be used to predict the prognosis of patients with cardiogenic shock.

Microcirculatory assessment of patients under VA-ECMO

Background

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an effective technique for providing emergency mechanical circulatory support for patients with cardiogenic shock. VA-ECMO enables a rapid restoration of global systemic organ perfusion, but it has not been found to always show a parallel improvement in the microcirculation. We hypothesized in this study that the response of the microcirculation to the initiation of VA-ECMO might identify patients with increased chances of intensive care unit (ICU) survival.

Methods

Twenty-four patients were included in this study. Sublingual microcirculation measurements were performed using the CytoCam-IDF (incident dark field) imaging device. Microcirculatory measurements were performed at baseline, after VA-ECMO insertion (T1), 48–72 h after initiation of VA-ECMO (T2), 5–6 days after (T3), 9–10 days after (T4), and within 24 h of VA-ECMO removal.

Results

Of the 24 patients included in the study population, 15 survived and 9 died while on VA-ECMO. There was no significant difference between the systemic global hemodynamic variables at initiation of VA-ECMO between the survivors and non-survivors. There was, however, a significant difference in the microcirculatory parameters of both small and large vessels at all time points between the survivors and non-survivors. Perfused vessel density (PVD) at baseline (survivor versus non-survivor, 19.21 versus 13.78 mm/mm², p = 0.001) was able to predict ICU survival on initiation of VA-ECMO; the area under the receiver operating characteristic curve (ROC) was 0.908 (95 % confidence interval 0.772–1.0).

Conclusion

PVD of the sublingual microcirculation at initiation of VA-ECMO can be used to predict ICU mortality in patients with cardiogenic shock.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1519-7) contains supplementary material, which is available to authorized users.